Charging device for electrical fuses



March 10, 1931. H. RUHLEMANN v CHARGING DEVICE FOR ELECTRICAL FUSES Filed Dec.

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UHID MASCHEMENFABRIK, A CDEPORATION F GERMANY SIGNQE TO DU$SELDO GDIG DEVICE FOR ELECTRICAL FUSES application filed December 16, 1928, Serial Ho. 414,486, and in Germany June 6, 1929.

This invention is an improvement over ply U. S. Patent No. 1,711,693, granted May The invention relates to a charging device for supplying electric current to electrical fuses, to be used as time, percussion or double fuses for projectiles, bombs, mines, or the like, and which are provided with two condensers, connected in opposition to each other and serving to supply the ignition current.

' An electrical diagram of such a fuse and the cooperating charging connections is repre- Sented in Fig. 1 of the drawing, while Fig. 2 illustrates a modified form of the invention.

The fuse A, for example, a percussion fuse, contains two condensers e and 7, similar poles e and f of which are directly connected together, while their second poles, 6 and f are connected together through a percussion 29 contact 9 and an electrical ignition substance k. Condenser f is also shunted by a high resistance i for the purpose of unequally varying its voltage relatively to that of condenser e.

The ignition energy is supplied to the fuse, before use of the latter, from a source of current provided in the charging device. For this purpose, the fuse is provided with three terminals k k and k of which 70 leads to 30 the condenser coatings e and 3, k to the coating f and k, to the coating e To impose the voltage of the source a on the fuse the charging device is provided with a three-pole switch 8, movable in the direction indicatedby the dotted lines, Fig. 1. The object of the present invention is to prevent an incorrect charging, as well as the possibility of a premature ignition of the fuse. Such premature ignition might occur,

for example, if, in the closing of the switch, contact were made only or at first with the poles 1: and 10 of the fuse; In that case, only the condenser 7 would be charged and there would be a difierence of potential at the igniting substance it between the coatings f and e of the two condensers, which would cause immediate ignition of said substance if the percussion contact 9 were accidentally Y closed.

Such charging of one condenser only is prevented by the construction and arrangement of the contact terminals of the source of current accordingto thepresent inventlon.

In the form of Fig. 1, the three poles 8;, 8 and 8 of the switch 8 of the source a are so formed and connected together that the poles s and 8 when the switch is thrown in, will always first be connected to the contacts k and 70 of the two condenser coatings f and 6 which are connected together through the igniting substance h. Only then will the second pole of the battery a be connected through contacts 8 and 70 to the condenser coatings f and e which are directly connected together. Thus the similar poles s and 8 of the source, as is the case in the form illustrated, may have different potentials,

although the difierence must be-less than the voltage necessary for ignition, or they may be separated from each other, or else shortcircuited together at the same potential.

The operation of the igniter is, of course, obvious. After its removal from the source, in which the above described steps are reversed in order, the switch terminal 8 will always be first disconnected, and afterwards the terminals 8 and 8 together. The condenser f discharges itself through the high resistance 2', and a potential difierence is built up between the condenser coatings f and e sufiicient to ignite the substance h, but only after a predetermined period of time;

In the form of Fig. 2, the switch of the charging system B is formed, for example, as a plunger with two contacts 8 and The contact 8,, which engages the igniter contacts 10 and 7: is extended at its forward end by a metal pin 8 which is insulated "from the current-conducting contact 8 In charging the condensers, that is, when the plunger is moved in the direction of the arrow, the pin 8 will first make a short-cir-T cuit between the condenser poles f, and e which are connected together through the igniting substance k and only thereafter will the condenser system be supplied with current. After the short-circuit is formed between f and e it is immaterial whether the contact 8 is first closed onthe common contact leading to the condenser coatings f and e,, or whether the contact st; is first closed on the condenser poles f and e which are connected together. Due to the short-circuit caused by the pin 8 just before the beginning of the charging operation, it is always assured that both condensers e and f will be safely charged at the same time,

I claim as my invention 1. Means for charging electric fuses provided with two oppositely-connected condensers, one pole of one condenser being .directly connected to the pole of the same sign of the other, and the other poles being con.- nected through an igniting substance, comprising fixed contact terminals for said condenser circuits, and cooperating movable contact terminals for the power circuit, one

of said movable contact terminals having an insulated metal extension to first short-circuit the condenser circuit through said substance before the power circuit is connected to the condenser circuits. 1

2. Means for charging electric fuses provided with two condensers connected in opposition with one another for storing the igniting current, one pole of one condenser being directly connected to the pole of like sign of the other, and the other poles being connected to one another through an igniting means, containing fixed contact members connected with the condensers of the fuse, and a switch comprising suitable opposing contact elements connected with the poles of the source of current, the said contact elements of the source of current being mechanically connected with one another and varying in length in groups in correspondence with their polarity, the contact elements of the one polarity being lengthened with respect to those of the other, in order that in applying the switch the contact members leading to the condenser terminals which are connected to one another through the igniting means of the fuse may be the first to make contact.

In testimony whereof, I aflix my signature.

HERBERT Rlj-HLEMANN;

mea re 

